It's already been said by one of the developers that the NCAA doesn't want a playoff used in the game. It's one of those image control things.
I think he was talking about Div II and Div III playoffs. I presume the NCAA would only veto an FBS playoff, since it doesn't happen in real life. Div II and III do have playoffs in real life, so it would be silly to veto that if EA decided to include those divisions.